I really can't tell you what is best for your situation, I can only tell you what has and has not worked for me!
My experience is that lies and deception are very destructive of any relationship. My first wife and I were both hiding things from ourselves and each other. After 20 years together our mutual discovery helped destroy the marriage.
I have now been with my present wife for 20 years, and we have been very open with each other.
There ARE some things we chose not to share, but we tell each other that "yes I am interested/own/do/whatever, but I would rather not share that at this time". It has worked for 20 years - so far LOL.
13 of those years were living together on a sailboat as we sailed around the world. It sounds romantic (it IS!), but with 200 sq ft of living area and only one other human being for 100 miles around you can't keep much secret from each other!
Couples who do that tend to be either very very close or split, there are very few in between. You really do depend on each other for your lives!
Oh yes, if you really feel guilty about something and you don't understand why, then a shrink can help you sort out the feelings.
In my case I was raped when I was 4 years old and blamed myself for "letting" it happen. It was pure hell to deal with that discovery, but nowhere near as bad as the guilt that I laid on myself for 40 years.
You have done the hardest and most important thing though - you have started to talk about the situation!